idle timing on 98 200efi

[20vector]

hello all.got question for y'all.on sticker on my motor says idle timing is 4 degrees ATDC.i read that is engine warm and in foward gear.originally timing was set at 0 degrees when i checked it at cranking speed with ECM disconnected.i rechecked it later in water to make sure.my problem is it was running real rough just in foward gear.i back it back down to 0.it ran smoother.was wondering if i should put back to 4 degrees ATDC and try raising idle or something or it being at 0 is ok.it says in book 0 to 9 degrees ATDC but on sticker it says 4 ATDC.and i heard to follow sticker if it has one.thanks again in advance.

 

[20vector]

Re: idle timing on 98 200efi

another thing i want to add is i recently disconnected my idle stabilizer. after i disconnected it i adjusted my WOT timing to 23 degrees from 22 degrees and that was it. didnt know if i had to do some other adjustments or not. one problem is after i adjusted it back to 0 degrees and the rough idle im getting now i cant remenber if that was how it was before i adjusted it. i know for sure when i had it at 4 degrees ATDC like what it says on sticker it definely ran alot worse at idle. either way it was set when running anything above idle seemed to be running good both times.thanks as always

 

[20vector]

Re: idle timing on 98 200efi

any ideas

 

[jeffersondodson561]

Re: idle timing on 98 200efi

Have you verified TDC?

 

[20vector]

Re: idle timing on 98 200efi

i checked it what i believed to be TDC on #1 while using screw driver thinking #1 was at top as i didnt have one of those tools it shows to use in the book to make sure #1 is at TDC. i plan on rechecking it to make sure again. i checked everything else i believe. i even hooked idle stabilizer back up and still runs rough while in no wake zone. if i bump it to 1000 rpm it smooths out but at 750 rpm it seems to be running to rough. i might be wrong i just cant remenber for sure it might of ran this rough the whole time i had it. but only noticed it when i disconnected idle stabilizer and adjusted WOT timing from 22 degrees to 23 degrees. if anybody can think of anything please holla.

 

[20vector]

Re: idle timing on 98 200efi

yeah when i believed #1 was at TDC the indicator was pointing at .462 BTDC. so thinking all marks were still good but i plan on picking up a dial indicator. just read how to get to 462 on regular dial indicator instead of having to use a quicksilver one that cost $150.

 

[jeffersondodson561]

Re: idle timing on 98 200efi

You could use a piston stop tool and get same results, much cheaper.

 

[20vector]

Re: idle timing on 98 200efi

where can i get one of those piston stop tools? and does it have the dial on it also? also was wondering if you know the thread size on mercury spark plugs? i seen some dials on ebay that i guess you have to modified to get them to mount in spark plug hole. do you got a model that you can recomend to me that works well and comes with a mount that works on mercury? thanks so much for y'alls time.

 

[jeffersondodson561]

Re: idle timing on 98 200efi

Just search for it on the a search engine. Basically you disconnect the battery, remove all the plugs and install the stop tool in #1 cylinder and rotate the flywheel until contact is made with the tool. It is best the lower unit be removed, once contact with the tool is made you mark the flywheel where the timing pointer is. Reverse the rotation of the flywheel until contact is made again and mark the flywheel where the timing pointer is. At this point you will have 2 marks on the flywheel. Take a piece of paper and cut it to measure between the two marks following the curvature of the flywheel. Then fold the piece of paper in half and mark the fold point on the flywheel. This will be the middle true TDC mark. Bring the middle mark up to the timing pointer, if it aligns with the timing pointer and your mark is on TDC it is good, if it is off when your pointer is aligned with the center mark adjust your timing pointer to TDC. It seems complex but basically you are using the tool as a base mark.

 

[Faztbullet]

Re: idle timing on 98 200efi

You use a piston stop tool on a Johnrude not a Merc. The Johnrude pointer is set at TDC and the Merc at .462 thousands. The difference is the Johnrude's ignition system gains timing at RPM where a Merc retards at RPM. That the reason you should/cannot set static max spark on Johnrude by cranking, they need to be running with a test wheel.

 

[jeffersondodson561]

Re: idle timing on 98 200efi

Agreed the dial indicator is best way to do this but I could not justify spending $100+ for a tool that you are only going to use once. However I have used both once my old boss showed me. I was using the dial indicator and he used the piston stop tool, both revealed TDC. The high speed/idle speed stablizer only retards ignition above 5600, other wise it advances it by as much as 6 degrees. Similar to Mercruiser's Means Best Timing igntion control module.

 

[20vector]

Re: idle timing on 98 200efi

hello all. borrowed dial indicator from a buddy. went threw the whole procedure a few times and everytime my timing marks lined up good. so this being said my idle timing is set now at 0 degrees where it was when i originally checked it. on sticker in motor says idle timing should be set at 4 degrees ATDC. when i set it there and ran it idling around ran real rough. really noticed issues when comming off plane to idle after running a bit would be super rough idling knowing something wasnt right. so put it back to 0 degrees and runs alot better at idle and could be how it was running before i adjusted it but i cant remenber. in my book it says it can be from 0 to 6 degrees but heard always follow whats on sticker. main thing i didnt know since i took off idle stabilizer off if i had to do some other adjusting? thanks for all the help info anything else you can think of please holla.

 

[Faztbullet]

Re: idle timing on 98 200efi

The high speed/idle speed stablizer only retards ignition above 5600, other wise it advances it by as much as 6 degrees.

Hate to disagree but engines with and without stablizer/advance modules(3 types) you allways set the max timing higher at cranking speed because the way the ignition is designed ,it will retard timing as rpm increases. Examples :early 150 cranking setting is 18? and running is 16? and it has only a stablizer which only advances timing if engine rpm falls below 600 rpm or it shorts out causing preignition thru the bia's circuit.

 

[jeffersondodson561]

Re: idle timing on 98 200efi

Did you disconnect the idle stabilizer when you were setting idle timing? The white/black wire. Also needs to be disconnected for WOT timing adjustment. And make sure your throttle plates are synced. You may need to inspect TPS voltage as well.

Fazt I believe you are correct after poking my head in the manual it gives 0D077248 thru
0D122746 carbureted models as having that model idle/high speed advance module P/N 93772A3.

 

[20vector]

Re: idle timing on 98 200efi

yeah had stabilizer disconnected whole time i was setting timing along with the ECU disconnected setting at cranking speed. yeah thats the stabilizer i have on my motor the one that advances the timing only when drops below 600 rpm. the one people have issues with messing up motors when it shorts out. pretty sure mine wasnt working anyway but reguardless mine disconnected now. i need to recheck my TPS setting again and will get back with yall. thanks again

 

[20vector]

Re: idle timing on 98 200efi

been reading that the 4 degrees ATDC idle timing is a starting point to set at while still on trailer and to readjust once in water. was wondering if that meant that i could advance it enough to smooth it out. that would probably put idle timing guessing would be around 4 degrees BTDC. in my book it says idle timing setting is 0 to 9 degrees ATDC. i got it around 0 degrees where it was when i first checked it. read that i could advance it to fine tune it once in water but didnt know if i could advance it that much. as always thanks in advance